I bought one and built it up about 20 years ago. It was one of the steel bodied coal wagons. It seemed easy enough to make, though I found the bufferheads to be rather fragile and vulnerable to abuse. Other then that, and the underneath to be fragile, they seem good to me. (It is that they are built with scale looks in mind rather then durability).
To conclude, I found them to be rather nice kits. My experience with them is limited though to building one and buying a second or third on the secondhand market.

Parkside Dundas kits (now Peco) I have built lots of these and I am delighted with them. They fit together very easily and can best be made using liquid poly applied with a fine brush. A fine needle file to clean up any excess plastic is useful and of course a modelling knife to remove components from the sprues. I find a flat sheet of glass is useful to build the model on to ensure that all the parts are true. I use a plate glass screen protector from a 1950s TV, but a smooth kitchen chopping board from Poundland will do just as well.

I buy and use the adaptor blocks to fit Bachmann mini couplings but of course there are a number of alternatives. Wheels run in brass top hat bearings (supplied) which makes them free running. Instructions are reasonably good, and it pays to have a dry run first if you are not familiar with these kits. I can build a 4 wheel wagon in well under an hour but I have had a lot of practice..

hi oldshed
i have built virtually the whole parkside range and ratio (both now owened by peco)plus many variations of the same.also most of the dapol and cambrian range. i have found both parkside and ratio good quality and easy to build . the latter two are also good but some of the molds do tend to warp and if care not taken will produce an uneven model
bye any of the basic model and give it a go .the tools required are a model knife,small files,abrasive cloths,a selection of small drill bit and holder,square and straight edge and a set of small tweezers .also as sugested by ld&cr use liquited poly
jaysix